Plastic compositions

ABSTRACT

Plastic Compositions containing epoxy resins and bis-phenoxy compounds having the formula: ##STR1## WHEREIN Z is bromine, m and m&#39; are each integers having a value of 1-5 and alkylene is a straight or branched chain alkylene group having 1 to 6 carbon atoms.

The prior art considered in conjunction with the preparation of thisapplication is as follows: U.S. Pat. Nos. 2,130,990; 2,186,367;2,329,033; 3,666,692; 3,686,320; 3,658,634; German Pat. No. 1,139,636;German Pat. No. 2,054,522; Japanese Pat. No. (72) 14,500 as cited inVolume 77, Chemical Abstracts, column 153737k (1972); ChemicalAbstracts, Volume 13, column 448⁵ ; Chemical Abstracts, Volume 31,column 7045⁹ ; and Journal of the Chemical Society, pages 2972-2976(1963). All of these publications are to be considered as incorporatedherein by reference.

The present invention relates to plastic compositions containing epoxyresins. More specifically, the present invention covers plasticcompositions containing epoxy resins and certain bis-phenoxy compounds(hereinafter defined) as flame retardants for said plastic compositions.

Epoxy resins and utility thereof are known in the art as exemplified byEpoxy Resins, I. Skeist, (Rheinhold Plastics Applications Series),Rheinhold Publishing Corporation, New York, 1960 and Modern PlasticsEncyclopedia 1972-1973, Vol. 49: No. 10A, October, 1972, pages 38, 40,147, 148, 222E, 222F and 229-231 and which publications are in totoincorporated herein by reference.

The need for flame retarding epoxy resins has also been recognized inthe art as exemplified by U.S. Pat. No. 3,347,822 and Modern PlasticsEncyclopedia, ibid, pages 222E, 222F, 229-231, and 456-458 and whichpublications are in toto incorporated herein by reference.

The resultant disadvantages in the utilization of various prior artmaterials as flame retardants for epoxy resins include, withoutlimitation, factors such as thermal migration, heat instability, lightinstability, non-biodegradable, toxicity, discoloration and the largeamounts employed in order to be effective. Thus, there is always ademand for a material which will function as a flame retardant in epoxyresins and concurrently will not, by incorporation therein, adverselyeffect the chemical and/or physical and/or mechanical properties of theresultant epoxy resin plastic composition.

The prior art problem of providing a flame retarded epoxy resincomposition having desired chemical, physical and mechanical propertieshas now been substantially solved by the present invention and theabove-described disadvantages substantially overcome.

Accordingly, one of the main objects of the present invention is toprovide epoxy resin plastic compositions which are flame retarded.

Another object of the present invention is to provide a material forepoxy resin plastic compositions which will not substantially adverselyeffect the chemical and/or physical and/or mechanical properties of saidcompositions.

A further object of the present invention is to provide a flameretardant which is economic and easy to incorporate into epoxy resinplastics without being degraded or decomposed as a result of blending orprocessing operations.

It has been found that the foregoing objects can be obtained by theincorporation of a new class of bis-phenoxy compounds in epoxy resins tosubsequently provide flame retarded compositions which exhibitoutstanding chemical, physical and mechanical properties.

The bis-phenoxy compounds used in the present invention compositionshave the formula ##STR2##

In Formula I above, Z is bromine, m and m' are each an integer having avalue of 1 to 5 inclusive and "alkylene" is a straight or branched chainalkylene group having from one to six carbon atoms and includes, withoutlimitation, groups such as --CH₂ --; --(CH₂)₂ --; --(CH₂)₄ --; ##STR3##

It is to be understood that all the compounds falling within Formula Iabove and as heretofore defined are generically described herein as"bis-phenoxy" compounds.

Representative, but without limitation, of said bis-phenoxy compoundsare the following ##STR4##

In general, the bis-phenoxy compounds are prepared by reacting ahalogenated phenol with a halogenated alkane at elevated temperatures inthe presence of a basic material such as alkali metal hydroxides,carbonates, bicarbonates, oxides and hydrides. The preferred alkalimetals are potassium and sodium. Where one desires to increase, forexample, ease of handling the reaction mass, solvents such as ketones(e.g. acetone, methyl ethyl ketone, and methyl iso-butyl ketone),alcohols (e.g. methanol, ethanol, iso-propyl alcohol, butyl alcohol andglycols), or aqueous solvents (e.g. water, a mixture of water andalcohol and a mixture of water and ketone) can be employed. The desiredend product i.e. the bis-phenoxy compound, can be recovered from thereaction mass via various methods such as distillation orcrystallization. Where the end product requires recovery viacrystallization, various aromatic solvents such as benzene, toluene,xylene, dichlorobenzene and the like can be used.

Specifically, the bis-phenoxy compounds are prepared according to thefollowing reactions: ##STR5##

In the above reaction, X is halogen, preferably chlorine and alkylene isthe same as herein defined. Where m and m' are different integers, thenequivalent molar portions of the particular halogenated phenol are usedwith equivalent portions of dissimilar halogenated phenol.

The above reaction is conducted at temperatures ranging from thefreezing point of the initial reaction mass to the boiling pointthereof. Preferably the temperatures are from about 40° to about 200° Cand more preferably from about 50° to about 175° C. It is to beunderstood that the reaction can be conducted under sub-atmospheric(e.g. 1/10-8/10 atmospheres), atmospheric or super-atmospheric (e.g.1.5-10 atmospheres) pressure. Preferably, the reaction is carried out atatmospheric pressure.

The above-described processes can be carried out with conventional,readily available chemical processing equipment. For example, aconventional glass-lined vessel provided with heat transfer means, areflux condenser and a mechanical stirrer can be advantageously utilizedin practicing any of the preferred embodiments of the inventiondescribed in the examples set forth herein.

The amount of bis-phenoxy compound employed in the present inventioncompositions is any quantity which will effectively render the expoxyresin containing composition flame retardant. In general, the amountused is from about 1 to 25% by weight, based on the total weight of thecomposition. Preferably, the amount employed is from about 5 to about20% by weight. It is to be understood that any amount can be used aslong as it does not substantially adversely effect the chemical and/orphysical and/or mechanical properties of the end polymer composition.The amount utilized, however, is such amount which achieves theobjectives described herein.

It is to be understood that the term epoxy resins as used herein meansthose materials which, based on ethylene oxide, its derivatives orhomologs, form straight chain thermoplastics and thermosetting resins,e.g., by condensation of bisphenol and epichlorohydrin to yield athermoplastic which is converted to a thermoset by active hydrogencontaining compounds, like polyamines and dianhydrides and the like.

Thus the epxoy resins used in the present invention compositions is anyepoxy resins herein defined and which one so desires to flame retard. Itis to be understood that the epoxy resins used can be a "virgin"material, i.e. substantially free of additives such as stabilizers,plasticizers, dyes, pigments, fillers, and the like, or the epoxy resinscan have additives (such as those mentioned and described herein)already contained therein or added concurrently with or after theaddition of the bis-phenoxy compounds.

Another facet of the present invention relates to the use of certainmetal compounds with the bis-phenoxy compounds to promote a cooperativeeffect therebetween and thus enhance the flame retardancy of theresultant plastic composition as compared to the flame retardancy ofeither one component used separately. These "enhancing agents" are fromthe group antimony, arsenic, bismuth, tin and zinc-containing compounds.Without limitation, examples of said enhancing agents include Sb₂ O₃,SbCl₃, SbBr₃, SbI₃, SbOCl, As₂ O₃, As₂ O₅, ZnBO₄, BaB₂ O₄.sup.. H₂ O,2.sup.. ZnO.sup.. 3B₂ O₃.sup.. 3.5H₂ O and stannous oxide hydrate. Thepreferred enhancing agent is antimony trioxide.

The amount of enhancing agent employed in the present inventioncompositions is any amount which when used with said bis-phenoxycompounds will promote a cooperative effect therebetween. In general,the amount employed is from about 1 to about 15%, preferably from about2 to about 10%, by weight, based on the total weight of plasticcomposition. Higher amounts can be used as long as the desired endresult is achieved.

It is also within the scope of the present invention to employ othermaterials in the present invention compositions where one so desires toachieve a particular end result. Such materials include, withoutlimitation, adhesion promotors; antioxidants; antistatic agents;antimicrobials; colorants; flame retardants such as those listed onpages 456-458, Modern Plastics Encyclopedia, ibid, (in addition to thenew class of flame retardants described herein); heat stabilizers; lightstabilizers; pigments; plasticizers; preservatives; ultravioletstabilizers and fillers.

In this latter category, i.e. fillers, there can be mentioned withoutlimitation, materials such as glass; carbon; cellulosic fillers (woodflour, cork and shell flour); calcium carbonate (chalk, limestone, andprecipitated calcium carbonate); metal flakes; metallic oxides(aluminum, beryllium oxide and magnesia); metallic powders (aluminum,bronze, lead, stainless steel and zinc); polymers (comminuted polymersand elastomerplastic blends); silica products (diatomaceous earth,novaculite, quartz, sand, tripoli, fumed colloidal silica, silicaaerogel, wet process silica); silicates (asbestos, kaolimite, mica,nepheline syenite, talc, wollastonite, aluminum silicate and calciumsilicate); and inorganic compounds such as barium ferrite, bariumsulfate, molybdenum disulfide and silicon carbide.

The above mentioned materials, including fillers, are more fullydescribed in Modern Plastics Encyclopedia, ibid, and which publicationis incorporated herein (in toto) by reference.

The amount of the above described materials employed in the presentinvention compositions can be any quantity which will not substantiallyadversely effect the desired results derived from the present inventioncompositions. Thus, the amount used can be 0%, based on the total weightof the composition, up to that percent at which the composition canstill be classified as a plastic. In general, such amount will be fromabout 0 to about 75% and specifically from about 1 to about 50%.

The bis-phenoxy compounds can be incorporated in to the epoxy resins atany processing stage in order to prepare the present inventioncompositions. In general, this is undertaken prior to fabrication eitherby physical blending or during the process of forming epoxy resins perse. Where one so desires, the bis-phenoxy compounds may be micronizedinto finely divided particles prior to incorporation into the epoxyresins.

EXAMPLE I

An epoxy resin (Epon 828, a product of Shell Chemical Company and thereaction product of bisphenol A and diglycidyl ether) is utilized as thebase resin in order to prepare 26 formulations. With the exception offormulation No. 1, the particular bis-phenoxy compound (and the antimonytrioxide enhancing agent where indicated) is incorporated into the epoxyresin by adding both to the epoxy resin which is contained in a 16 ounceflask in a water bath. This addition occurs during the heat-up of theepoxy resin to approximately 85° C. After the bis-phenoxy (and Sb₂ O₃)addition to and dispersion therein, a hardner (Dow's DEH 50, 4,4'-methylenedianiline) is added over a period of about 15 minutes inorder to insure dissolution therein.

The resultant mixture is then poured into a mold which consists of twovertically positioned glass plates which are covered with cellophanefilm and separated by a 1/8 inch Teflon gasket. The mold is then placedin an oven and the epoxy resin formulation cured for 16 hours at 55° C,then 2 hours at 125° C and finally 2 hours at 155° C. The epoxy resinformulation is then removed from the oven and cooled and then the solidsheep (epoxy resin formulation) is cut to test specifications in orderto provide samples therefor. The percentages by weight of thebis-phenoxy compound and Sb₂ O₃ used in the formulations are listed inTable I.

Portions of the solid samples of each respective formulation (Nos. 1-26)prepared according to the above described procedure are then subjectedto two different standard flammability tests, i.e. UL 94 and ASTMD-2863-70. The UL 94 is, in general, the application of a burner to atest specimen (strip) for a certain period of time and observation ofcombustion, burning, and extinguishment. This procedure is fully setforth in Underwriters' Laboratories bulletin entitled UL 94, Standardfor Safety, First Edition, September 1972 and which is incorporatedherein by reference. ASTM No. D-2863-70 is a flammability test whichcorrelates the flammability of a plastic specimen to the availableoxygen in its immediate environment; this correlation is stated as anOxygen Index, O.I., level predicated upon the percent oxygen in thegaseous medium which is required to just provide a steady state ofcontinuous burning of the plastic specimen. This ASTM method is fullydescribed in 1971 Annual Book of ASTM Standards -- Part 27, published bythe American Society For Testing and Materials, 1916 Race St.,Philadelphia, Pa.; this publication is to be considered as incorporated(in toto) herein by reference.

The results of these flammability tests are shown in Table I.

                                      TABLE I                                     __________________________________________________________________________    FLAMMABILITY DATA FOR EPOXY RESIN PLASTIC COMPOSITIONS                        CONTAINING BIS-PHENOXY COMPOUNDS                                              __________________________________________________________________________    FORMULATION                                                                            BIS-PHENOXY                                                                           COMPOUND                                                                             ENHANCING AGENT                                                                          OXYGEN INDEX                               NO.      NO.     %      Sb.sub.2 O.sub.3, %                                                                      %        UL 94                             __________________________________________________________________________    1.       --      0      0          27.5     SB                                2.       III     3.0    0          30.8     SB                                3.       III     7.5    0          33.0     SB                                4.       III     10.0   0          33.5     SB                                5.       III     12.5   0          34.0     SB                                6.       III     3.0    3          38.0     SE-1                              7.       III     7.5    3          38.3     SE-1                              8.       III     10.0   3          38.9     SE-1                              9.       III     12.5   3          40.0     SE-0                              10.      III     3.0    5          38.2     SE-1                              11.      III     7.5    5          38.7     SE-1                              12.      III     10.0   5          39.5     SE-1                              13.      III     12.5   5          40.5     SE-0                              14.      II      3.0    0          30.5     SB                                15.      II      7.5    0          31.0     SB                                16.      II      10.0   0          31.5     SB                                17.      II      12.5   0          32.0     SB                                18.      II      3.0    3          36.5     SE-0                              19.      II      7.5    3          37.0     SE-0                              20.      II      10.0   3          37.3     SE-0                              21.      II      12.5   3          37.9     SE-0                              22.      II      3.0    5          37.1     SE-0                              23.      II      7.5    5          37.4     SE-0                              24.      II      10.0   5          38.0     SE-0                              25.      II      12.5   5          38.5     SE-0                              26.      II      15.0   3          38.0     SE-0                              __________________________________________________________________________

Referring to Table I, the bis-phenoxy compound formula II or III relatesto the structural formulae heretofor set forth; a difference of 2% inthe Oxygen Index values is considered significant; and the UL 94 valuesare on a graduated scale wherein the highest degree to lowest degree offlame retardancy is respectively SE-0, SE-1, SE-2, SB and Burns.

The results shown in Table I demonstrate the unique effectiveness ofthese bis-phenoxy compounds as flame retardants for epoxy resins.Specifically, formulation No. 1 (the control) had a O.I. of 27.5 and UL94 value of SB. In Nos. 2-5 and 14-17, the use of the particularbis-phenoxy compound results in a significant increase in fireretardancy as measured by O.I. (While these formulations also had a SBrating, UL 94, the individual U.L. rating has a wide range of values andthus the O.I. number is, in this case, more indicative of increasedflame retardancy).

The use of an enhancing agent such as Sb₂ O₃ to promote a cooperativeeffect between such agent and the bis-phenoxy compound is fullydemonstrated via the results obtained from testing formulation Nos. 6-13and 18-26. The highest UL 94 ratings and significantly higher O.I.values are obtained.

EXAMPLE II

Portions of the solid samples of Formulation Nos. 1-26 preparedaccording to the above described procedure of Example I are subjected tothe following ASTM tests in order to ascertain other properties of theresultant plastic composition:

1. Tensile Strength (at break) : ASTM Test No. d638-61T;

2. flexural Strength : ASTM Test No. D790-63;

3. flexural Modulus : ASTM Test No. D790-63;

4. notched Izod Impact : ASTM Test No. D256-56; and

5. Heat Distortion Temperature (HDT) : ASTM Test No. D648-56.

Each of the aforementioned ASTM Tests are standard tests in the art andare utilized collectively in order to ascertain the efficacy of apolymeric system as an overall flame retarded composition for commercialapplication. All of these ASTM Tests are to be considered asincorporated herein by reference.

The results of these ASTM tests show that the physical properties of thepresent invention compositions are basically the same (except O.I. andUL 94 values) as the plastic material without the flame retardant (i.e.formulation No. 1). Thus, there is no substantial adverse effect on thephysical properties of the plastic material when the novel compounds areincorporated therein.

EXAMPLE III

The procedure of Examples I and II are repeated except that thebis-phenoxy compound used corresponds to Formula IV, heretofor setforth, instead of Formulae II and III. Substantially the same resultsare obtained using the Formula IV compound as those obtained usingFormulae II and III compounds.

EXAMPLE IV

The procedure of Examples I, II and III are repeated except that theenhancing agent used is zinc borate instead of Sb₂ O₃. Substantially thesame results are obtained using zinc borate as those obtained using Sb₂O₃. The other enhancing agents are predicted to be equally effective.

EXAMPLE V

Strip samples of each of Formulation Nos. 1 (control) through 26 TableI, are subjected to light stability tests via the use of a"Weather-Ometer", model 25/18 W. R., Atlas Electrical Devices Company,Chicago, Illinois. Utilizing an operating temperature of 145° F and a50% relative humidity, each strip is subjected to 200 hours of"simulated daylight" via the use of a carbon arc. The results show thatafter 200 hours, there is no significant discoloration in any striptested and which demonstrates that the present invention compositionsare highly resistant to deterioration by light.

EXAMPLE VI

Samples of each of Formulation Nos. 1 (control) through 26 Table I, aresubjected to temperature (thermal) stability tests via the use ofthermal gravimetric analysis (TGA). This test employed the use of a"Thermal Balance", modes TGS-1, Perkin-Elmer Corporation, Norwalk, Conn.and an electrical balance, Cahn 2580 model, Cahn Instrument Company,Paramount, Calif. The results of these tests show that the bis-phenoxycompound containing Formulations had more than adequate stability formelt processing and subsequent heat aging (i.e. high temperatureapplications) and thus demonstrating that the particular bis-phenoxycompounds are quite compatible with the epoxy resin material. Thebis-phenoxy compound stability thus aids in providing sufficient flameretardancy at the epoxy resin decomposition temperature. This test alsodemonstrates that the bis-phenoxy compounds do not exhibit migration.

The bis-phenoxy compounds are subjected to toxicity tests and it isfound that these compounds are not toxic orally, not irritating to theeye and not irritating to the skin, all as measured by the guidelines ofthe Federal Hazardous Substances Labeling Act.

In view of the foregoing Examples and remarks, it is seen that thecompositions, which incorporate the bis-phenoxy compounds, possesscharacteristics which have been unobtainable in the prior art. Thus, theuse of the bis-phenoxy compounds in epoxy resins as flame retardantstherefor is quite unique since it is not possible to predict theeffectiveness and functionality of any particular material in anypolymer system until it is actively undergone incorporation therein andthe resultant plastic composition tested according to various ASTMStandards. Furthermore, it is necessary, in order to have commercialutility, that the resultant flame retarded plastic composition possesscharacteristics such as being non-toxic. Use of the bis-phenoxycompounds has accomplished all of these objectives.

The above examples have been described in the foregoing specificationfor the purpose of illustration and not limitation. Many othermodifications and ramifications will naturally suggest themselves tothose skilled in the art based on this disclosure. These are intended tobe comprehended as within the scope of this invention.

What is claimed is:
 1. A plastic composition comprising an epoxy resinand a flame retardant, said flame retardant consisting of a compoundhaving the formula ##STR6## wherein (a) Z is bromine; (b) m and m' areindependent and are integers having a value of from 1 to 5; and (c)alkylene is a straight or branched chain alkylene group having from oneto six carbon atoms.
 2. The composition as set forth in claim 1 whereinthe amount of said compound employed is from about 5% to about 25% byweight, based on the total weight of said composition.
 3. Thecomposition as set forth in claim 2 wherein the alkylene group is CH₂.4. The composition as set forth in claim 2 wherein the alkylene group is(CH₂)₂.
 5. The composition as set forth in claim 2 wherein the alkylenegroup is (CH₂)₃.
 6. The composition as set forth in claim 2 wherein thealkylene group is (CH₂)₄.
 7. The composition as set forth in claim 2wherein the alkylene group is ##STR7##
 8. The composition as set forthin claim 2 wherein the alkylene group is ##STR8##
 9. The composition asset forth in claim 2 wherein the alkylene group is ##STR9##
 10. Aplastic composition comprising an epoxy resin and a flame retardant,said flame retardant consisting of a compound having the formula##STR10##
 11. A plastic composition comprising an epxoy resin and aflame retardant, said flame retardant consisting of a compound havingthe formula ##STR11##
 12. The composition as set forth in claim 1wherein there is also present a flame retardant enhancing agent whichpromotes a cooperative effect with said compound to increase the flameretardancy of said composition.
 13. The composition as set forth inclaim 12 wherein said enhancing agent is antimony trioxide.
 14. Thecomposition as set forth in claim 10 wherein there is also present aflame retardant enhancing agent which promotes a cooperative effect withsaid compound to increase the flame retardancy of said composition. 15.The composition set forth in claim 14 wherein said enhancing agent isantimony trioxide.